120 Wisconsin Academy of Sciences, Arts, and Letters. 
EXPLANATION OF PLATE VII, 
All figures except dissections are drawn with a camera. Magnifica¬ 
tion in diameters given after explanation of each figure. 
Fig. 1. Dorsal view showing tracheal system and alimentary tract. 
Secondary longitudinal trachea, SI., thrown to the outside of the 
main trunk. A., dorsal branch entering head. B., ventral branch 
entering head. Pr., prothorax. Mo., mesothorax. Mt., metatho¬ 
rax. Circles on the ends of the tracheal branches indicate points 
where same enter external respiratory filaments. Oe., oesophagus. 
C., crop. Md., mid-intestine. Mp., Malpighian tubule. S., small 
intestine. L., large intestine. R., rectum. X 8. 
Fig. 2. Surface view of portion of chitinous lining of oesophagus, p., 
posterior border. X 300. 
Fig. 3. Longitudinal section of oesophageal valve. An., anterior. Ch., 
chitin. Pm., peritrophic membrane. Cm., circular muscle. Lm., 
longitudinal muscle. X., point showing end of chitin and begin¬ 
ning of peritrophic membrane. X 110. 
Fig. 4. Longitudinal section through junction of mid- and hind-intes¬ 
tine. Mp., Malpighian tubule. Pm., peritrophic membrane. X., 
beginning of chitinous layer, Ch., of hind-gut. Cm., circular 
muscle. Lm., longitudinal muscle. Y., beginning of flattened epi¬ 
thelium of small intestine. Pg., pigment granules. X 110. 
Fig. 5. Section through nidus of mid-intestine. Cm., circular muscle. 
Lm., longitudinal muscle. Bm., basement membrane. Pm., peri¬ 
trophic membrane. X 285. 
Fig. 6. Longitudinal section through rectal valve. An., anterior. Ch., 
chitin. E., epithelium. Cm., circular muscle. Lm., longitudinal 
muscle. X 90. 
Fig. 7. Surface view of epithelial cells of large intestine. X 190. 
Fig. 8. Section of same. Cm., circular muscle. Pm., peripheral mem¬ 
brane. X 285. 
